The present invention relates to an apparatus for turning a negative film carrier applied to a photograph printing apparatus, and more particularly, to an apparatus for turning a negative film carrier having an improved construction such that interference with peripheral elements caused by the film carrier's turning is prevented.
FIG. 1 is a schematic diagram showing the overall structure and component layout of a conventional printer for use in photograph printing. Here, printing paper is wound on a roll 2 in the upper portion of a printer body 1, and a container 12 for enclosing roll 2 is provided. A tray 18 for receiving the printing paper after being cut into pieces by a cutter 17 installed adjacent thereto is provided in the upper portion of the other side of printer body 1. Disposed along the path of the printing paper between container 12 and tray 18 is an exposing portion 13 and a processing portion 16. The exposing portion 13 is arranged vertically and located adjacent to an optical system (described below), to thereby expose the downwardly proceeding printing paper, while the processing portion 16 is provided with a multitude of transfer rollers and processing chambers, for processing and fixing the exposed printing paper. In addition, a cavity 14 where the exposed printing paper stays temporarily is provided in the lower portion of exposing portion 13.
The optical system includes, aligned along a single optical axis OA, a light source 4 for generating light that exposes the printing paper, a color filter 5 for passing a specific wavelength of light emanating from light source 4, a light diffusion box 6 for uniformly diffusing filtered light from color filter 5, and a table 7 positioned above light diffusion box 6, for supporting a negative film carrier 8. Further, again along optical axis OA, an image forming lens 9 is provided above table 7, and a shutter 10 for controlling the passage of light from image forming lens 9 is provided above the lens. In addition, a mirror 11 for reflecting the light passed through shutter 10 along optical axis OA' toward exposing portion 13 is situated at the proper angle above the shutter.
In an actual exposure, the light generated from light source 4 passes through the negative film (hereinafter also referred to as "film") on film carrier 8 and forms image light. Then, the image light passes through image forming lens 9 and reaches printing paper 3 via mirror 11, thus forming an image on the printing paper. In the formation of the image on the printing paper 3 as above, the exposure time depends on the opening time (speed) of shutter 10. Also, it is possible to achieve proper color or black-and-white photography through one exposing operation.
In FIG. 2, a portion of light diffusion box 6 and film carrier 8 are shown in detail. Film carrier 8 consists of a print mask 34 with a rectangular opening (window) of a predetermined size formed therein (e.g., 36.times.24 mm) and transferring rollers 32 and 33 near opposite sides of the print mask and separated by an interval A in the film transferring direction shown by arrow FT. Each transferring roller is composed of a pair of contiguous roller members. The film is fed between the roller members and transferred in one direction (as shown by the arrow FT in FIG. 2) by rotation of the roller members. After one frame of the transferred film is positioned exactly in the window of print mask 34, a photograph is obtained by exposing the printing paper as hereinbefore described. Here, light diffusion box 6 is used for uniformly illuminating the entire area of the window of print mask 34. Light diffusion box 6 comprises a housing having a rectangular cross-section, a sawtooth glass and a diffusion board which are attached at opposite ends of the housing. The upper edge portion of the light diffusion box is positioned between transferring rollers 32 and 33 of film carrier 8 and is adjacent to print mask 34. (Here, though depicted separately from the carrier supporting table 7 in FIG. 1 which is merely representative of an optical system, light diffusion box 6 is actually fixed to the table 7.)
The print paper used in the photograph printing apparatus is in the form of a long roll as described above. When a picture from the film is printed on the print paper, two conditions must be accommodated according to the desire print size or orientation. That is, the window of print mask 34 needs to be oriented horizontally for portrait prints and vertically for landscape prints. As such. film carrier 8 can be turned 90.degree. while supporting the film.
The length of the film to be used in the printing varies according to the number of pictures taken. If there is only one picture on the film, that is, the film length equals the length of one picture portion (or frame), it is impossible to feed the film into the film carrier 8 (i.e., into either transferring roller 32 or 33) so that the one picture on the film is properly aligned with the window of print mask 34. Therefore, the film must be at least two pictures long.
FIG. 3. shows an example of film 25 having a length of two pictures 40. Here, a length B (about 38 mm) corresponds to each picture segment, that is, the length of one picture (36 mm) plus half of the approximately 4 mm interval between the pictures.
Therefore, to transfer the minimum length of film (corresponding to two picture segments)into film carrier 8, the relation between the interval A of FIG.2 and length B of FIG. 3 must satisfy the relation A&lt;2B. That is, the distance between transferring rollers 32 and 33 is required to be less than 76 mm.
As described above, in the conventional technique, it is necessary to meet the condition A&lt;2B, and to turn film carrier 8 by 90.degree. to accommodate both portrait and landscape printing.
However, since light diffusion box 6 is fixed on carrier supporting table 7 and part of the light diffusion box 6 (i.e., the upper edge portion) extends between the transferring rollers 32 and 33 of film carrier 8, when the film carrier turns, transferring rollers 32 and 33 are caught on the upper edge portions of the light diffusion box 6.
One of two methods can be considered to solve this problem. First, the light diffusion box 6 may be moved farther from transferring rollers 32 and 33, so that the upper edge portion of light diffusion box 6 is no longer positioned between transferring rollers 32 and 33. However, this increases the distance between the light diffusion box and print mask 34 of film carrier 8, resulting in reduced light usage efficiency. Second, transferring rollers 32 and 33 may be lifted when film carrier 8 turns, to thereby separate them from light diffusion box 6. Thereafter, the film carrier would be loaded at a predetermined position. However, this complicates the mechanism.